Digital Breast Tomosynthesis (DBT) enables 3-D reconstruction of multiple levels of breast tissue from a series of 2-D projections acquired at different angles. Its main advantage is that it generates a volumetric dataset that allows resolution of tissue superposition ambiguities that are often present in projection mammograms. DBT is currently being investigated for use as a primary screening modality but issues related to radiation exposure and detection performance remain. In a previous retrospective observer performance we found that DBT in combination with Full Field Digital Mammography (FFDM) reduced recall rates by 30% while maintaining sensitivity, compared to FFDM alone, but the combined examination doubled radiation exposure. When DBT alone was compared to FFDM the reduction was only 10%. A 30% reduction in recall rates would be sufficient to justify incorporating DBT into screening protocols, but not if it requires doubling the radiation exposure over that of FFDM. The intent of this proposal is to determine whether the 30% reduction can be achieved without acquiring separate FFDM and DBT studies by using a synthetic FFDM, comprised of a high-resolution (70-5m) projection of appropriately reconstructed DBT data, as a substitute for the directly acquired FFDM. To test this we will develop algorithms for deriving the synthetic FFDM from the DBT data and then perform an observer performance study that measures performance of 1) FFDM alone followed by FFDM combined with traditional DBT, and 2) traditional DBT alone followed by DBT combined with the synthetic FFDM. Mode 1 has previously been shown to provide the performance gains discussed above, but requires twice the radiation dose of mode 2. The two study arms enable us to measure performance of FFDM alone, FFDM + DBT, DBT alone, and DBT + synthetic FFDM. The performance study will have 8 radiologists read 100 cases in both modes and report BIRADS scores and ROC-type scores. Each case will include an FFDM and a DBT acquired in a single procedure on our Hologic DBT system. This work will be significant because, if our goal of replacing the FFDM acquisition with a projection derived from the DBT data is successful, then it will be possible to achieve the 30% reduction in recall rates without the increased radiation exposure. PUBLIC HEALTH RELEVANCE: Breast tomosynthesis is a recently introduced imaging modality that can significantly reduce recall rates, while maintaining screening sensitivity, if used in conjunction with mammography in a screening environment. However, this combined exam doubles the radiation exposure over that required for mammography alone. This project tests various strategies for incorporating DBT into breast cancer screening environments that may be able to retain the performance improvements without the increase in radiation exposure. This could greatly reduce the number of women unnecessarily recalled because of a false positive screening result.